The present invention relates to dental articulators and, more particularly, to an improved articulator which allows for accurate interchangeability of dental casts.
The purpose of a dental articulator is to simulate the jaw or condylar movements of a patient. This instrument enables a dentist to obtain the necessary diagnostic information for the treatment of occlusal irregularities, such as malocclusion, and the fabrication of dental casts or "dentures". In U.S. Pat. No. 3,452,439, issued to Robert L. Lee on July 1, 1969, there is described a system of jaw movement simulation wherein the dynamic movement of a patient's jaws is recorded, and from this information plastic blocks are formed. These blocks have three-dimensional openings or pathways cut therein that may be used with a dental articulator to simulate or almost duplicate the particular patient's jaw movement.
In the above-referenced U.S. Pat. Nos. 4,034,474 and 4,034,475, there is disclosed a simplified system for measuring jaw movements, with such information being useful in setting and operating dental articulators. It is further suggested in those patents that plastic guide blocks of the type disclosed in the earlier Lee patent be classified according to certain characteristics of jaw movements to provide a series of average value blocks from which the pair most closely fitting the measurements of a particular patient's condylar movements may be selected. Such guide blocks have curved walls which produce movement that closely simulates a patient's particular condylar movements, thus enabling a dentist to treat accurately an occlusal or denture problem without requiring the presence of the patient.
In the fabrication and use of dental casts, it is often necessary to transfer the cast from one articulator to another several times. Typically, a dentist or his assistant will take a mold of the patient's teeth and then give the mold to a lab technician for the preparation of the dental cast. Thus, it is important that the articulators be interchangeable to obtain consistent results.
In the past, differences in dimensional characteristics between articulators were largely ignored, thus leading to inaccuracies in the making and using of dental casts. Even small dimensional differences in articulators are crucial since small irritations caused by inaccurate dentures are easily detected in the mouth.
Certain manufacturers of articulators attempt to overcome this problem by providing auxiliary equipment, such as binoculars and cross-hairs, in order to accurately adjust the mounting of a cast in an articulator to eliminate the effect of dimensional irregularities among articulators. These devices, however, are costly and require more of a dentist's or lab technician's time.